The present invention relates to a central swivel joint comprised of a support beam and a central beam, whereby the support beam is rigidly connected to the centrally arranged oil pan of the motor of the farm tractor and the central beam is rotatably supported about its longitudinal axis relative to the support beam at a friction bearing comprised of a floating bearing and a stationary bearing.
For rotating a central beam about its longitudinal axis it is known to support the central beam with a radially guided floating bearing and a radially and axially guided stationary bearing relative to the support beam. The support means is rigidly connected to the oil pan of the motor arranged at the center of the tractor. The oil pan is thus a supporting component which connects the front axle and the rear axle on the one hand via the central beam and on the other hand via gear box casing, a coupling casing, and a flywheel casing. The bearing of the support beam in the interior of the central beam is embodied as a welded construction. The axial guiding of the stationary bearing is achieved by a bolt which is inserted transverse to the axis of rotation into an annular groove on the support beam. The known embodiment requires a plurality of components. It cannot be connected with the lubricating system of the motor because a return passage for the oil is very difficult to establish and the central beam must be prepared by complicated procedures in the form of a welded construction for receiving the bearing of the support beam. The insufficient lubrication results in a fast wear. Furthermore, the axial guiding of the stationary bearing is a weak point in view of the high axial forces.
It is therefore an object of the present invention to provide a central swivel joint of the aforementioned kind that can be manufactured in a more economic manner and which has an improved lubrication in order to increase the service life of such a central swivel joint.